Hydraulic press



'w. FERRls HYDRAULI-C'PRESS I Nov. 20, 1928.

lNVENTo/R. man?? firk/s' A TTORNE Y.

Nov. 20, '1928. r I

, w. FERRls mmRAULIf: PRESS Filed Nov.

ATTORNEY.

Patented Nov. 20, 192'8.

UNITED STATES 1,692,771 PATENT OFFICE.

WALTER FERRIS, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE OILGEAR COMPANY,

OF `MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN, If

HYDRAULIC PRESS.

Application led November 8, 1924 Serial No.v 748,634.

j This invention relates to hydraulic presses vand the like, and particularly to control mechanism therefor'.

In some commercial operations it is highly desirable that the machine employed be capable of exerting a certain predetermined pressure uponthe work and then to automaticallv withdraw therefrom, so as to permit the replacement of work in the machine. Such is the case, for instance, in assembling operations wherein the predetermined pressure is required to effect proper assembly. of

the parts operated upon.

One object of the present invention is the. provision of a hydraulic press of control mechanism by which theabove operation may be obtained.

Other *objects and advantages will appear from the following description of an illus'- trative embodiment of this invention. n

In the accompanying drawings: K Figure 1l is a. view inelevatiompartly in section, of a hydraulic press constructed in accordance with theV present invention. x

Figures 2 and 3 are similar Viewsillustrating the relative positions of the parts in different operating stages.

The press selected ior illustration comprises tho conventional C-frame 10, supported upon a base 11, and provided with the usual stationary bed 12 for receiving the work fw. A power cylinder 13is fixed in the upper portion of the C-frame in vertical position above the bed 12. The plunger 14 of the press is actuated by a piston 15 rcciprocable in the cylinder 13. i In this instance, a four-way valve ot appropriate form controls the delivery of fiuid to and from the opposite. ends of the cylin- '40 der 13. The valve shown comprises a piston having three heads 16, 17 and 18, integrally connected and rcciprocable as a unit in a'cyL inder bore 19 .of the valve casing 20. The

piston valve is controlled by a stem 21 con-A nected thereto and proiecting through one end of the casing. A pipe 22 connected with the 11p-per end of cylinder 13 communicates .it all times with that portier. of the valve casing between the heads 1G and 17 of the valve, and a pipe 23 connected with the lower end of 'the cylinder 13' communicates at allA `vtimes with that portion of the valve casing ',-between thei'heads17 and 18 of the valve. A l'iuidgdischarge pipe 24 communicates at all 5.5 times'with the upper end of the valve'casing and is provided with branch pipes, 25 and 26 opening into'the side of the valve casing and controlled by the heads 16 .and 18 of the valve. A fluid sup-ply pipe 27 enters the side of the valve casing at such point as to be controlled by the intermediate head 17 of the-valve. A l longitudinal duct 28 in the valve maintains communication between the end portions of the valve casing and is intersected by a transverse duct 29 in the head 17 of the valve.

The' arrangement is such that when the valve is in the intermediate position shown in Figure 1 fluid delivered through the pipe 27 enters the duct 29 and passes through the duct 28 into the upper end of the valve casing and is discharged through the pipe 24 without entering either of the pipesv 22 or 23. This is the position of the valve when the press is al. rest. By shifting the valve upwardly into the position shown in Figure 2 the supply pipe 27 is uncovered by the head 17 and communication is established between this pipe and pipe 22 leading to the upper end of the cyliu der 13. In the upper position of the valve branch pipe 26 is likewise uncovered by the head 18 and placed in' communication with the pipe 23 leading to the lower end of the cylinder. Fluid is thus admitted to the upper end of the cylinder through pipes 27 and 22 and discharged through pipes 23, 26 85 and 24 to efl'ect a downward travel of the pistou and press plunger. By shiftingthe valve downwardlv into the position shown in Figure 3, communication is established between pipe 27 and pipe 23 through the valve 9o casing above thel head 17. and communication 4 is established het- Ween branch Ziipe 25 and pipe 22. Fluid is then delivered to the lower end of cylinder 13 through pipes 27 and 23 and discharged from the upper end through pines 22. 25 and 24- to effect an upward travel of the piston and plunger. i

In this instance. pipes 24 and 27 are connected to the intake and discharge sides, respectively. of a pump 30. The pump may be loo -of any appropriate type. that shown being f. extending upwardly through a block 33 secured to the head of the press. vThe upper end of this rod is rigidly connected through an arm 31 with the stem 21 of the valve so as to move -in unison therewith. Rod 31 ex'- tends loosely through the end 34 of a rigid arm 35, iixedrto and carried by the press.

plunger. A collar, adjustably fixed to the rod 31, is arranged to be engaged and lifted by the end 34 of the arm when the plunger approaches the upper limit of its stroke. ,A-

coiled compre ion spring37, confined-within the block 33, surrounds the rod 31, and bears at all times upon a'lug 38, fixed to the rod, so as to yieldably lpress the rod downwardly. A latch 39 is mounted upon a horizontal pivot pin 40 within the block 33 beneath the lug 38. This latch is provided with an upright nose portion 41 adapted to engage beneath .and releasably retain the lug 38 in its upper extreme position when the rod 31 has been elevated. A spring pressed plunger 42 within the block 33 bears at all times upon the horizontal tail'portion 43 of the latch and tendsto rock the latch into lug engaging position. .c The plunger 42 is pressedL by .a spring 44, housed within a bore 45 in the block 33 and confined betweenthe plunger and a lug 46 screwed into the upper open end o the bore. The tension of the spring may be varied to best suit the conditions at hand by turning the plug 46. The plug may be fixed in anyposition of adjustment by a lock n'ut 47 or the like. fluid actuated plunger 48, mounted in a bore 49 in the block 33, is arranged to bear upwardly upon the tail portion 43of the latch. The bore 49 communicates with pipe 22 through a pipe 50.

Any appropriate means, such as a foot Alever 51, is provided by which the operator may shift the rod 31'. In this instance, the lever '51 is mounted intermediate its ends upon a `tilted pivot 52 with its inner end 53\ bearing upwardly against the lower end 54 Figure 1 illustrates the position of the several parts when the-press is at rest. It will be .notedirom' an inspection of this figure that the pressplunger 14 is in its` uppermost position, and that the rod 31 is supported in auf-intermediate position by engagement of the arm 35 beneath the collar 36. The Vcontrol pipey 24 to the pump without entering pipes 22 or 23 as above explained.

' I To begin an operating-cycle the operator depresses the outer end 55 of the foot lever.

vfigure, thereby opening Comunication between pipes 27 ,and 22, and between pipes 23 and 24,

and causing the piston and plunger to begin,

a downward or'working stroke, as above explained., rThe plunger 14 continues down-V wardly unt-il forced' against the work. When this occurs the pressure established between the plunger and work is immediately transmitted through the piston 15 to the Huid in the upper end of the cylinder and thence throughv pipes 22 and 5() tothe bore 49. The instant that the pressure in the bore 49 becomes great enough to cause the plunger 48 to rock the l latch 39, against the pressure of spring 44, the nose portion 41.is withdrawn ,from beneath the lug 38, and the rod 31 shifts downwardly, under the influence of spring 37, into' the position shown in Figure 3. This action of the rod, ofcourse, shifts the control valve into the position shown in this figure and communication is established between pipesl .27 and 23, and between pipes 24 and 22, thereby causing the press plunger. to begin its upward or return stroke, as above explained.

l OG

The plunger 14 continues its upward or return stroke. until the end 34 of the arm 35 has engaged beneath the collar -36 and lifted theA rod 31, and lconsequently the valve, into the intermediate position shown in Figure 1.

When this has occurred pipes 22 and ,23 are Y again disconnected from pipes 24 and 27 and the press comes to rest.

,Since the fluid pressure necessary to rock Vthe latch.39 into releasing position is dependent upon the pressure exerted by the spring 44, and since this fluid pressure is proportional to the pressure between the plunger and the work, it will be noted. that the pressure exerted by the press upon the work may be varied and controlled by adj usting the spring 44.

In some instances, it is desirable to effect. a slight delay in the return stroke of the plunger or to control the degree of pressure than is possible with the mechanism thus far described. In such instances provision .is made for restricting the low of fluid through the pipe 50. This is ordinarily accomplished by connecting al coil ofsmall diameter tubing 55 in serieswith this pipe. Thiswillresult applied to the work with greaterN accuiacyl in a delayed action of the plunger 48 and aVM consequent delay in the tripping of the latch 39. 4By the application of a relief valve to cessive pressures, due to this delayed action,

' is avoided, and b adjusting such valve the pressure to'be esta lished between the plunger and Work can be very accurately determined. A standard form of relief valve for this purpose is shown in section in Figure l. AIt comprises a casing 56 having a passage 57 communicating through pipe 58 With the fluid supply pipe 27. A spring loaded valve 59 controls the flow of fluid through passage 57, and a screw vplug G is employed for determining the pressure in the spring 61. The casing 56 is preferably connected to the pipe 24; through a pipe 62, so that fluid'escaping past the valve 59 may be returned to the pump. By adjusting the plug 60, the maximum pressure in the circuit and consequently 'i the pressure applied by the 'press plunger to the Work mayl be determined With extreme Various changes may be made in the embodimentof the invention hereinabove specifically described, Without departing from or sacrificing any of the advantages of the. in-

I claim: i l. lIn a hydraulic press lthe combination of a plunger, fluid actuated means for reciprof` eating said plunger toward and. from the work, means for. controlling the direction of movement of said plunger, latch mechanism 'for releasably retaining said control means in one position to effect movement of said plunger toward the Work, and means responsive to the pressure exerted by said plungerupon the Work'for releasing said latch mechanism to effect movement of said plunger away from the Work. l

2. Ina hydraulic press the combination of a plunger, fluid actuated means for reciprocating said plunger toward and from the work, means for controlling the movement of said plunger, means under the control of the operator for shifting said control means into -one position to effect movement of said plunger in one direction, latch mechanism for releasably retaining said control means in said'position, and means responsive to thev pressure exerted by said plunger upon the Work for releasing said latch mechanism to effectmovement of said plunger from the Work.

3. In a hydraulic press the combination of, a plunger, fluid actuated means for driving said plunger, valve mechanism for controlling the direction of movement of said plunger, means under the control of the operator for shifting` said valve mechanism to effect--A movement of said plunger toward the Work, latch mechanism for releasably retaining said mechanism in one position, and means responsive to the pressure exerted by said plunger upon the Work for releasing said latch mechanism to effect movement of said plunger from the Work.

4. In a hydraulic press the combination of a plunger, fluid actuated means for driving said plunger, means responsive to an increase in pressure in said fluid actuated means for reversing the movement of said plunger, and means including 4a restricted fluid passage for delaying the action of said reversing 5. In a hydraulic press the combination of a plunger, fluid actuated means for driving said plunger, valve mechanism for controllingthe action of said means, means responsive yto an increase in pressure in said fluid .actuated means for shifting said valve mechanism to reverse the movement of said plunger, and means lincluding a restricted fluidY the action of said last y ,hing means, and means for preventing an exvention as defined in lthe appended-claims?y cessive pressure in said 'fluid actuated means.

7. The combination of a driven member, hydraulic means for driving said member, control means therefor, latch mechanism for releasably retaining said control means `in one position, and means responsive to a predetermined change in hydraulic pressure in said hydraulic means for releasing said latch mechanism.

8. The combination of a reciprocablemember, hydraulic means for driving said member, reversing mechanism therefor, latch mechanism for releasably retaining said mechanism in one position, and means responsive to an increase in hydraulic pressure in said hydraulic means for releasing said latch mechanism.

9. The combination of a hydraulically actuated member, a pump for supplying a driving liquid thereto, a reversing valve,

latch mechanism for releasably retaining said valve in one position, and means responsive to an increase in pressure in said driving liquid for releasing said mechanism.

10. The combination of a driven member, hydraulic means for driving said member, a reversing valve, means under the control of the operator for operating ,said valve to ef'- fect movement of said member in one direction, latch mechanism for releasably retaining said valve in one position, pressure responsive means for operating said latchl mechanism to thereby effect operation of said valve to reverse the movement of said member, and means movable vvith said member and operable to shift said valve into neutral position to thereby bring said member to rest.

In witness whereof, Ihereunto subscribe my name'this 25th day of October, 1924.

' WALTER FERRIS.

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